1. Field of the Invention
This invention relates to apparatus for developing photographic materials, such as photographic sheets, photographic film and the like.
In particular, the invention relates to such a developing apparatus which has two or more containers for respective treating baths, through which the photographic material must travel in succession.
2. The Prior Art
Not all photographic materials are processed in the same way. Some require more processing steps or different treating chemicals than others. To make developing apparatus of the type here under discussion more flexible, i.e., more adaptable to these different requirements, it has already been proposed not to use a single large container and to subdivide it into a plurality of chambers for the treating baths, but instead to use a plurality of individual containers each of which is dimensioned to accommodate one of the treating baths. The apparatus can then be adapted for different requirements by simply adding or removing the requisite number of containers.
Such containers have a removable cover which closes them against the entry of light. Also, to permit travel of the photographic material into and out of the respective container, each such container has ports. The ports of successive containers are connected by guide elements through which the photographic material travels.
From time to time it is necessary to remove the cover of the respective container, e.g., for inspection purposes, for cleaning or for other reasons. When this occurs, it is important to prevent the incoming light from passing through the guide elements into the preceding and/or succeeding containers. For this purpose it has been proposed to mount a movable flap or door at each port, which closes automatically when the cover is removed. The disadvantage of this proposal is that the flaps contact the photographic material and tend to damage it (e.g., scratch the photographic emulsion). This is a particular danger if the machine is in operation and the material therefore in movement, when the cover is removed.
According to another proposal, lighttraps are arranged between the ports of the successive container. These traps prevent the travel of light between the containers by defining an interior passage in which the photographic material (e.g., a film) is forced to travel in a series of loops. Since the containers must usually be located close together to save space, the trap cannot be long and hence the loops must be very tight so that the requisite number of loops can be accommodated. Photographic material which is processed in this kind of apparatus must be available as a long band; hence, successive films, film strips or the like are glued or otherwise joined together to form this band which then travels through the apparatus. When the joints travel through the tight loops in the prior-art light traps, however, they tend to separate because of the small radii through which the material is deflected as it negotiates the loops.